The present invention relates in general to plastic, snap-on overcaps or capseals that are constructed and arranged to assemble onto and over the assembly of a threaded closing plug as threaded into a flange that is captured by a portion of the corresponding container or drum end. A drum end is able to be fitted with a threaded opening for dispensing of the drum contents, as is well known in the art. One way to do so, and the way described herein, uses an internally-threaded flange that includes an outer peripheral edge that is shaped so as to be securely held in place by crimping drum end material over, under, and around this outer peripheral edge. Various peripheral edge configurations are contemplated for the flange, including serrations, a hex shape, or a smooth peripheral edge. The internally-threaded flange is closed by the use of a threaded plug. An annular gasket is preferably used at a selected interface location between the plug and the flange or alternatively between the plug and the drum end material that is formed over and around the flange.
When transporting product in drums of the type described herein, there may be opportunities for the product to be accessed by unauthorized persons. In order to address this possibility, tamper-evident structures are often provided that are intended to provide a visual indication of any tampering attempts. Since it is not practical to employ means that might prevent any chance of tampering, an adequate compromise is found by at least providing an indication of a possible tampering attempt. Knowing that a tampering attempt may have occurred permits the shipper or end user to check the product before dispensing that product from the container or drum.
Various tamper-evidence schemes have been conceived of over the years with varying degrees of success. Whether from a cost perspective or from an efficacy perspective, each of the prior art schemes has something within its design and/or use that can be improved up on. The present invention focuses on some of what are believed to be design deficiencies or shortcomings with some of these earlier tamper-evident approaches. For example, those prior designs that do not create a sealed interface around the closing plug expose the closing plug to the accumulation of debris in, on, and around the plug. If the selected tamper-evident approach is configured so as to seal off the assembled closing plug, this is seen as an improvement to the design of tamper-evident structures for threaded closing plugs and their corresponding flange assembly into the drum end.
When a plastic overcap or capseal is used as the tamper-evident structure of choice, the typical construction calls for removal of this cap or at least a portion of this cap prior to being able to unscrew the threaded closing plug. The method of removal and the ease of manipulation for the user are further considerations that might be improved upon. In this same context, it is seen as an improvement if some visual reminder could be provided to the user, indicating that a tampering attempt may have occurred or at least a reminder of that possibility. If a warning label or marking is left behind after any attempt at tampering, the user is given a further reminder of what might have occurred. If a portion of the capseal is left connected to the closure, then this serves to alert the shipper or end user that the remainder of the protective capseal has been removed. Attempts to remove the portion left behind can scratch the surrounding portions of the closure and/or drum end, providing a visual warning. It is therefore incumbent upon the end user, if any of these warning signs are present, to check the contents before those contents are dispensed. The present invention provides a design for a snap-on capseal that is seen as providing improvements that are novel and unobvious.